Consist one computer only
Group of 2 or more computers in the same building
Group of computers in different building
Group of computers in different area
Electro mechanical device
Electrical device
Electronic device
Mechanical device
Agricultural pumps
Fabricating workshop
Water treatment plant
Electric traction
Power and control circuit are simple
Speed and design ratios have upper limits
Produce a simulated wave form
Heavy windings required
Green
Yellow
Red
Blue